Humidity affects the performance of von Frey monofilaments

Werner, Mads U.; Rotbøll-Nielsen, Per; Ellehuus-Hilmersson, C.

doi:10.1111/j.1399-6576.2011.02426.x

Cited by 23 publications

(25 citation statements)

References 16 publications

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“…The area of 2HA in normal skin surrounding the area of the heat injury was determined with a nylon filament (nominal value mean ± standard deviation: #18 [0.89 ± 0.05 N]; Stoelting Co, Wood Dale, IL) 31. The border was determined by stimulating in eight symmetric lines, each separated by an angle of 45 degrees converging towards the center of the heat injury.…”

Section: Methodsmentioning

confidence: 99%

Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model: a double-blind, randomized, placebo-controlled, five-arm crossover study

Ravn¹,

Secher²,

Skram³

et al. 2013

JPR

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PurposeOpioid therapy is associated with the development of tolerance and paradoxically increased sensitivity to pain. It has been suggested that buprenorphine is associated with a higher antihyperalgesia/analgesia ratio than μ-opioid receptor agonists. The primary outcome of this study was therefore to investigate relative differences in antihyperalgesia and analgesia effects between morphine and buprenorphine in an inflammatory pain model in volunteers. The secondary outcome was to examine the relationship between pain sensitivity and opioid-induced effects on analgesia, antihyperalgesia, and descending pain modulation.Subjects and methodsTwenty-eight healthy subjects were included. The study was a double-blind, randomized, placebo-controlled, five-arm crossover study with a multimodal (electrical, mechanical, and thermal stimuli) testing technique. After baseline assessments, intravenous infusions of morphine (10/20 mg), buprenorphine (0.3/0.6 mg), or placebo (normal saline) were administered over a 210-minute period, during which a cold pressor test, heat injury (47°C, 7 minutes, 12.5 cm2), and the first postburn assessment were done. After completion of the drug infusions, two additional postburn assessments were done. The subjects were monitored during each 8-hour session by an anesthesiologist.ResultsFor nearly all tested variables, significant dose-dependent analgesic effects were demonstrated. The median antihyperalgesia/analgesia ratio (secondary hyperalgesia/heat injury relative to placebo) for low-dose morphine was 0.01 (interquartile range: −6.2; 9.9), 0.00 (−2.4; 2.1) for high-dose morphine, 0.03 (−1.8; 2.1) for low-dose buprenorphine, and 0.00 (−3.2; 1.1) for high-dose buprenorphine (P > 0.466). There were no significant differences in opioid responses between high and low pain-sensitive subjects (P > 0.286). High-dose buprenorphine, compared to placebo, was associated with a significantly enhanced action of the descending inhibitory pain control system (P = 0.004).ConclusionThe present study, using multimodal testing technique, could not demonstrate any significant differences between morphine and buprenorphine in the profiles of antihyperalgesia and analgesia. Only high-dose buprenorphine was associated with a significant effect on the descending inhibitory pain control system.

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Section: Methodsmentioning

confidence: 99%

Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model: a double-blind, randomized, placebo-controlled, five-arm crossover study

Ravn¹,

Secher²,

Skram³

et al. 2013

JPR

View full text Add to dashboard Cite

show abstract

“…The area of secondary hyperalgesia in normal skin surrounding the area of the heat injury was determined with a nylon filament (nominal value 18 [mean ± standard deviation: 0.89 ± 0.05 N; Stoelting Co, Wood Dale, IL) 28. The border was determined by stimulating eight symmetric lines each separated by an angle of 45 degrees converging towards the center of the heat injury.…”

Section: Methodsmentioning

confidence: 99%

Prediction of pain sensitivity in healthy volunteers

Ravn¹,

Frederiksen²,

Skovsen³

et al. 2012

JPR

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PurposeThe primary objective of the present study was to evaluate predictive parameters of the acute pain score during induction of an inflammatory heat injury.Patients and methodsHealthy volunteers (50 females/50 males) were included in the study. The predictive potential of gender, anthropometric (body surface area, body mass index), psychological (anxiety, depression, vulnerability), and psychophysical (quantitative sensory testing, conditioned pain modulation) variables in estimating the pain response to a validated heat injury (47°C, 7 minutes, area 12.5 cm2) were investigated. All assessments were made in duplicate sessions separated by 21 days (median).ResultsThere were three main findings in this study. First, a predictive model of pain sensitivity during the heat injury, including both genders and using multiple regression technique, could account for 28% of the variance (P < 0.0001), but gender-related differences in the final model could not be demonstrated. Second, the results confirmed significant gender-related differences in perception of electrical, pressure, and cold pressor stimuli (P < 0.002). Third, positive correlations between anthropometric data and pain perception during electrical and pressure stimuli were demonstrated (P < 0.001 and P < 0.005, respectively).ConclusionThe study demonstrated predictability of acute pain sensitivity, and although gender-related differences in pain perception were demonstrated, no gender-related differences in pain sensitivity could be shown. Interestingly, positive correlations between anthropometric data and pain perception were shown for the first time.

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“…VF testing is the gold-standard method to evaluate allodynia in pain studies (30,31). VF and EVF tests both verify peripheral and central sensitization.…”

Section: Discussionmentioning

confidence: 99%

“…EVF testing is advantageous due to its ease of use with a single measurement evaluating the reaction to increased force. Although EVF testing is not detailed as VF, it still reveals allodynia in the head and forepaw (30,31). In human studies, VF testing is considered unreliable for repetition while EVF seems more reliable (31).…”

Section: Discussionmentioning

confidence: 99%

Nitroglycerin challenge induces lateralized headache in nasociliarynerve-ligated rats: implications for chronic migraine

et al. 2017

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Background/aim: Chronic migraine is a common debilitating disease with limited treatment options. We aimed to develop a novel model for chronic migraine by ligating the nasociliary nerve (NCL) and administering nitroglycerin (NTG) to exacerbate acute headache attacks. Materials and methods: Exacerbation of the headache was induced by NTG (10 mg/kg, subcutaneously) administered to male Wistar rats (n = 36) 14 days following unilateral NCL. Cutaneous and cold allodynia was tested using Von Frey (VF) filaments and acetone, respectively. Elevated plus maze (EPM) results and c-fos immunoreactivity of TNC were investigated. Results: NTG administration significantly decreased VF threshold values only in the nasociliary nerve (NCN) territory and the ipsilateral forepaw (P = 0.0001, P = 0.02). Cold allodynia developed in bilateral NCN territories (P = 0.013). The number/rate of entrance to open arms in the EPM was significantly decreased in NCN-ligated rats (P = 0.042, P = 0.035). Immunohistochemistry disclosed significantly increased c-fos-positive neurons in ipsilateral brainstem TNC compared to the contralateral side (brain stem LI ipsilateral 25.4 ± 4.7, contralateral 11.8 ± 1.9, P < 0.05) in chronic NCN-ligated rats exposed to acute NTG. Conclusion:The presented model provides a valid chronic migraine model relevant to humans, as NTG challenge in chronic NCL rats generated lateralized headache with cephalic and extracephalic allodynia, altered cold sensitivity, anxiety, and neuronal activation in the nociceptive laminae of brainstem trigeminal pain nuclei.

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Humidity affects the performance of von Frey monofilaments

Abstract: The data indicate that the hygroscopic properties of polyamide monofilaments must be taken into account for their reliable use in quantitative sensory testing.

Cited by 23 publications

References 16 publications

Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model: a double-blind, randomized, placebo-controlled, five-arm crossover study

Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model: a double-blind, randomized, placebo-controlled, five-arm crossover study

Prediction of pain sensitivity in healthy volunteers

Nitroglycerin challenge induces lateralized headache in nasociliarynerve-ligated rats: implications for chronic migraine

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